Drinkable omega-3 preparation and storage stabilization

ABSTRACT

A liquid nutritional and/or refreshing preparation is described to which an emulsion is added containing oils with polyunsaturated fatty acids and remedial substances in a water-based drink, in such a manner that the drink does not turn rancid within the storage time of the water-based phase, a method for its production and its application.

The present invention relates to a liquid nutritional and refreshingpreparation to which oils are added containing omega-3 fatty acids andremedial substances wherein the preparation does not turn rancid withthe storage time indicated for the liquid phase, a method for itsproduction and its application.

The human body is capable of producing most of the saturated fatty acidswhich it requires. Two polyunsaturated fatty acids, eicosapentaenoicacid (EPA) and docosahexaenoic acid (DHA), however, cannot besynthesised and have to be supplied through the diet. They are thereforecalled essential fatty acids (EF). EPA and DHA constitute the mostimportant so-called omega-3 fatty acids. Fish oil is known to be thebest source of these omega-3 fatty acids.

In Norway there is a long tradition of using cod liver oil as a dietarysupplement, due mainly to the fact that it was regarded as a valuablevitamin supplement. Only recently has the important role of fish oilbeen reported as a source of polyunsaturated fatty acids with the lastdouble bond placed at the third last carbon atom in the carbon chain(omega-3 fatty acid) (Dyrberg J., Bang H. O., Stoffersen E., Moncada S.and Vane J. “Eicosapentaenoic acid and prevention of thrombosis andatherosclerosis”, Lancet ii, 117–119, 1978). Subsequent research hasshown that these fatty acids reduce the risk of heart disease as well ashaving a positive effect on children's development, as well as on theskin. Results have also been disclosed indicating the positive effect ofthese fatty acids on certain mental illnesses, autoimmune diseases andjoint complaints. There are therefore many reasons for consideringtaking fish oil as a valuable dietary supplement, including thelong-term effect which this dietary supplement is now thought to have.The problem, however, has been and still is the taste which many peopleconsider to be unpleasant, both during ingestion and in subsequentregurgitation. Modern production methods to-day manufacture cod liveroil and fish oil with a taste which is not unpleasant, butpolyunsaturated fatty acids are highly unstable and are subject tooxidation when exposed to air, as well as auto-oxidation in concentratesof fish oil. These processes cause them to turn rancid, giving theproduct an unpleasant smell and taste.

In addition to the unpleasant taste of rancid fish oil, results havealso been disclosed which may indicate that oxidation products from fishoil are damaging to health (Kubow S., “Toxicity of dietary lipidperoxidation products”, Trends in Food Sciences & Technology, September,67–71 (1990)). Thus it is extremely important to provide fish oilproducts which are not oxidised before ingestion.

The production of cod liver oil is known in the form of emulsions inorder to improve the taste but these are highly subject to oxidationduring storage as they are exposed to air. Methods are also known forproducing mixtures of marine and vegetable oils in a ratio of less thanone part marine oil to three parts vegetable oil (EP-A-0304 115), andfor improving the storage of edible oils and fat and their emulsions(BE-A-0668 727), but in this case marine oils are not mentioned. U.S.Pat. No. 4,826,702 describes a dressing consisting of a fish oil phaseand an aqueous phase which are stored separately and mixed immediatelybefore use in order to minimise oxidation of fish oils.

In CN 1108891 are ω-3 fatty acids added to milk by emulgating the fattyacids. The concentration of the ω-fatty acids is 0.01–0.1%, thus lowerthan is the present invention.

JP 08089167 relates to fermented milk whereto ω-3 fatty acids are addedin concentrations from 0.001–1 weight % and an antioxidant in anoil-in-water emulsion, with long storage time. This mixture does notcontain fish oil, preserving agent, nor vitamins, and the concentrationsof the ω-3 fatty acids are lower than in the present invention.

NO B 180148 relates to the production of an article of food containingω-3 fatty acids from fish oil in powder form in addition to vitamins,sweeteners and aroma. The concentration of fish oil is 0.22% and 0.25%(weight/volume). The method comprises production of a dry powder mixtureof fish oil and vitamins which thereafter is stirred into heated fruitor vegetable juice, and is differing essentially from the methodaccording to the present invention.

NO B 41943 relates to method wherein cod liver oil and another oil aremixed and thereafter added to nutritional or refreshing preparation,without adding vitamins, emulgators, sweeteners and preserving agents.The content of fish oil is lower than in the present invention.

NO A 954726 relates to fruit juices enriched with gamma linolenic acid(GLA) and dihomogammalinolenic acid (DGLA) and optionally EPA and DHA.This drink does not comprise fish oil, the fatty acids are derived fromplant oils.

NO A 954573 relates to milk products enriched with GLA and/or DGLA andoptionally EPA and DHA. This product does not comprise the samecomponents as in the present invention.

WO 00/04887 relates to a medicament to prevent or treat cardiovasculardiseases and comprises phytosterols and phytostannols from plants andω-3 fatty acids from plants or marine oils, and synergism between thephytosterols, phytostannols and the ω-3 fatty acids is maintained. Thepreparation is thus different from the present invention.

U.S. Pat. No. 5,567,730 relates to a method for stabilizing ω-3 fattyacids by dispersing ω-3 fatty acids, an acid derivative thereof and anoil or fat containing an ω-3 unsaturated fatty acid or an acidderivative thereof in an aquos solution without using emulgating agents.This invention differs thus essentially from the present invention.

U.S. Pat. No. 4,670,285 relates to a breast milk substitute whereinvegetable oil is mixed with at least one of an ω-6 fatty acid or ω-3fatty acid, wherein the latter may be contained in lipids from egg yolkor fish oil. The content of ω-3 fatty acids is less than 0.06% and themixture does not comprise the other compounds of the present invention.

In EP 0493439-B1 a product is described comprising a tube or a softplastic container made of an airtight material and containing anunhydrogenated marine oil preparation in the form of an oil-in-wateremulsion. The oil is composed of a cod liver oil or other marine oil orconcentrates or mixtures thereof, hereinafter designated as cod liveroil, and the amount of oil added to the emulsion is such that theemulsion obtains a mayonnaise or paste-like consistency, i.e. itcontains at least 65 weight % oil. The oil is mainly polyunsaturated andconstitutes between 66 and 88 weight % of the emulsion. The actual tubeor container is designed in such a manner that when it is used it iscompressed proportionally with the amount of emulsion remaining afterone dosage, with the result that no air space is formed in the containerand therefore no appreciable oxidation will occur in the cod liver oilproduct. During the manufacturing process this product is not in contactwith air and this absence of air prevents oxidation of the fish oil inthe product. Moreover, the content of vitamin E will act as anantioxidant and play an important role in the defence against freeradicals. The product consists of an oil-in-water emulsion (80:20;oil:water) with the viscosity of mayonnaise. The marine oils exist as adispersed phase with a diameter down to 1 μm in a continuous hydrophase.The packing factor for spherical particles of an equal size is known tobe a maximum of 74% and with an oil content above this, the lipidmicelles are in a disturbed geometrical structure. Despite this theemulsion retains its physical stability. The high oil content gives theemulsion a high degree of viscosity, which appears to help to preventthe polyunsaturates from being auto-oxidised. The emulsion is kept inairtight tubes, thus preventing oxidation during storage and dosing.

The above-mentioned products are composed of viscous emulsions andmayonnaise-like mixtures which it is not natural to ingest in order tocover the body's liquid requirements. So far the present inventors haveno knowledge ω-3 preparations in form of refreshing drinks and fruitdrinks to which fish oil is added in such a manner that it does not turnrancid over time under normal storage temperature in a refrigerator.

Furthermore the above-mentioned products produce the disadvantageouseffect that youngsters and children are not motivated to use and consumethe product, and if they are forced by their parents they may produce aserious dislike.

It is therefore an object of the present invention to produce ω-3preparations in form of refreshing drinks without the above-mentioneddisadvantages and a method for manufacturing such drinks. This object isachieved with the present invention, characterized by that which ispresented in the attached claims.

The daily dose of omega-3 fatty acids which is recommended to-day is1000 mg–2000 mg, which comprises 540 mg–1080 mg docosahexaenoic acid(DHA) and 385 mg–770 mg eicosapentaenoic acid (EPA). Known preparationswhich contain this are 4–6 gelatine capsules or 5 grams of fish oil/codliver oil containing approximately 20% omega-3 fatty acids. At thepresent time there are no other known ways of ingesting this daily dosewithout eating oily fish. The reason appears to be that no otherproducts exist which are palatable, practical to use and where theunsaturated fatty acids are not oxidised or auto-oxidised, and whichyoungsters and children accept

The object of the present invention, therefore, is to produce:

1. Ordinary consumer goods which tastes and looks like orange juice,skimmed milk or breast milk substitute which, despite the addition offish oil with polyunsaturates, still tastes and is perceived like thepure juice or milk product, with no trace of a fish oil taste, wherevitamins E and C are either present in the ingredients or are added.

2. A method for manufacturing the product which is of such a naturethat, during production and subsequently during distribution, storageand daily use (with shaking before use and daily reduction of thecontents of the package), the unsaturated fatty acids are stillunaltered in taste and no oxidation has taken place over a periodrepresenting the storage time of the water-based phase.

The present invention relates to a liquid nutritional and/or refreshingpreparation to which oil with polyunsaturated of fatty acids is added insuch an amount that when ingesting the preparation in a volume less thanthe body's daily liquid requirement, the supply of a recommended dailydose of omega-3 fatty acids is obtained. The fatty acids are added insuch a manner that neither oxidation nor auto-oxidation occurs duringthe preparation's storage time despite the fact that the drink's surfaceis in contact with air.

The manufacture of the preparation according to the invention isimplemented as follows: an emulsion containing 65–90 weight % oil, whichmay be vegetable or fish oil, alone or in combination, containing atleast 15 weight % omega-3 fatty acids, for example 66–88 weight % codliver oil or other marine oil, for example as described in EP-B-0493439,is stirred vigorously together with the water-based liquid phase so thatthe emulsion is comminuted in the liquid phase. Surprisingly, it wasshown that the oil product, like the basic emulsion, remained dispersedin the liquid phase during daily shaking in addition to the movements towhich a carton is naturally exposed during pouring into a glass andstorage in the refrigerator. The mixture ratio between emulsion anddrink may vary from 1:10 to 1:100, preferably from 1:20 to 1:40.

During manufacture a special emulsification method is employed for theoil with added omega-3 fatty acids, or the fish oil, which results inthe lipid omega-3 phase of an oil-in-water emulsion being made in such away that an emulsion is produced step by step, where in the first stepall the omega-3 oil is in the form of an 80% lipid phase where thehydrophase is an emulsifying agent for example egg yolk, to which inturn is added an aqueous solution of vitamin C. Also added in this stepare aromatic oils, sweetening agents, pH-regulating agents, water,conservation agents and vitamins. In other steps the liquid refreshingand/or nutritional phase (FNF) is added in such a manner that withregard to the aforementioned first step it is distributed in FNF and theratio between the lipid phase and the hydrophase remains unaltered fromthe first step. This mixing into FNF may be implemented by vigorousstirring in a commercially available food mixer or other suitable mixingdevices. The finished product will now comprise a system where the firststep's 2 phases are distributed in a relatively large amount of solutionwith a high content of vitamin C/ascorbic acid whose FNF is composed of,e.g., fruit juice, as a third phase.

Surprisingly, it was also shown that the polyunsaturated fatty acid inthe drink according to the invention were not oxidised in the course ofthe storage time of the water-based liquid phase (FNF). Without havingto commit ourselves to a specific theory, however, it appears probablethat auto-oxidation is not likely in a system where the distance is sogreat between the emulsion drops, where the oil in the emulsion has adiameter of approximately 1 μm. Oxidation due to the air stratum inbalance with the liquid surface can be reduced by a combination ofemulsifying agent, such as egg yolk to which vitamin C is added inaqueous solution, and the antioxidant, vitamin E which is either presentin the marine oil or is added to the basic material. The addition ofvitamin C in the form of, for example, fruit juice, or as such willprovide a synergistic effect by causing vitamin E to be regenerated.Even though it is known that vitamin C can regenerate vitamin E(Bjørnebo, G., E. Antioksidanter, in “Mat og medisin” Ed. Gunn-Elin Aa.Bjørneboe, Christian A. Drevon, Kaare R. Norum. Universitetsforlaget,Oslo, pages 207–216, 1994), the combination of egg yolk with vitamin Cis new and it is very surprising that the unstable polyunsaturated fattyacids were not oxidised by the air supply which is present over thesurface of the liquid in, for example, a cardboard carton which islifted and shaken daily. The combination of egg yolk, vitamin E in thelipid phase and vitamin C in the hydrophase forms a barrier against freeradicals, where vitamin C regenerates vitamin E which quantitatively isthe most important fat-soluble antioxidant. There is no evidence thatthis system is known to completely prevent discernible oxidation of thepolyunsaturated fatty acids within the given period.

The invention will now be further illustrated by examples which shouldin no way be considered limiting.

EXAMPLE 1

The example illustrates a drink according to the invention, based onorange juice.

The manufacture takes place in two stages, where in stage 1 an emulsionis produced containing omega-3 fatty acids, which in stage 2 are mixedwith orange juice in a ratio of 1:20 while being vigorously stirred inan emulsifier (Koruma disho s 160/400 5745, Germany). During storage,without movement, stage 1 will be separated from stage 2 and lie on thetop.

The content of ingredients is illustrated in Table 1.

TABLE 1 Stage Ingredients Amount (g) 1 Fish oil with 40% omega-3 8000 gEgg yolk 50 g Lemon oil or orange oil 100 g Sugar 477 g Salt 100 gCitric acid 200 g Water 500 g Preserving agents E211, 50 g E202, E218Vitamin C 63 g (Ascorbic acid) Vitamin E 10 g Total 10000 g 2 Orangejuice with 30 mg ascorbic acid/100 g - total 57 g 190000 g 200000 g

EXAMPLE 2

The example illustrates a drink according to the invention, based onorange juice.

The manufacture takes place as in Example 1, in two steps. If, insteadof orange juice, a concentrate of orange juice is used, water issupplied in an additional step 3, in amounts corresponding to the amountof water removed from the concentrate used in step 2.

EXAMPLE 3

The basic material consisting of 50 grams of Coromar® which containsfish oil, water, egg, vitamins (ascorbic acid, sodium ascorbate,alpha-tocopherol, folic acid), aroma (orange oil), preserving agent(potassium sorbate, sodium benzoate), sweetening agent (asulpham K,sodium cyclamate, sodium saccharinate), acidity regulating agent (citricacid), stabiliser (guarana kernel flour, xanthane rubber), was stirredinto 1 liter of orange juice by a domestic food mixer. This mixture willcontain a total of 13 grams of omega-3 fatty acids in the form oftriglycerides. 100 ml of this drink will give the recommended daily doseof 1.3 grams of omega-3 fatty acids.

EXAMPLE 4

The basic material consisting of 50 grams of Coromar® which containsfish oil, water, egg, cocoa, vitamins (ascorbic acid, sodium ascorbate,alpha-tocopherol, folic acid), aroma (peppermint oil), preserving agent(potassium sorbate, sodium benzoate), sweetening agent (asulpham K,sodium cyclamate, sodium saccharinate), stabiliser (guarana kernelflour, zanthane rubber), was stirred into 1 liter of chocolate milk by adomestic food mixer. This mixture will contain a total of 13 grams ofomega-3 fatty acids in the form of triglycerides. 100 ml of this drinkwill give the recommended daily dose of 1.3 grams of omega-3 fattyacids.

EXAMPLE 5

The Example illustrates breast milk substitute with full dose ω-3 fattyacids.

It is in Norway recommended that the amount of essential fatty acids inbreast milk substitute is equivalent to the amount of linolenic acid inthe mixture, i.e. 0.60 g/100 g breast milk substitute.

The preparation of 800 ml breast milk substitute according to theinvention is prepared as in Example 1, by mixing 100 g mixed breast milksubstitute with 2 g Coromar, prepared as in Step 1, Example 1, whereupon200 ml water is added in step 2 and vigorously stirred This content ofω-3 DHA and EPA is 0.60 g.

For all the preceding examples applies that if Step 2 of the preparationdoes not immediately follow Step 1, the product from Step 1 can bestored in an airtight container without being oxidised.

EXAMPLE 6

This example illustrates the lasting quality of the mixture in example2.

Orange juice with added Coromar® was made as described in example 1 andfilled in a 1-liter cardboard carton which was stored at approximately+4° C. in an ordinary refrigerator. Once a day the carton was removed,shaken and approximately 30 ml was poured out and sampled by a testpanel. This panel was composed of 20 randomly selected persons of bothsexes. The drink was assessed according to the following criteria:rancid smell and taste, taste of fish oil, oily feeling in the mouth andjuice taste. After 30 days, where the content had been reduced by 30 mlevery day, no rancidity of the fish oil was registered on the basis oftaste. This experiment was intended to correspond to normal storage in arefrigerator in a kitchen and shows that the lasting quality is withinthe lasting quality indicated for the orange juice and was thussatisfactory as such.

EXAMPLE 7

This example demonstrates a comparison between orange juice with addedCoromar® as in Example 2 and orange juice without Coromar®.

The test panel was composed as described in Example 4. They werepresented with sample A and sample B in unmarked, clear glasses. SampleA consisted of a drink as described in Example 2, stored in arefrigerator at 4° C. for 60 days. Sample B consisted of pure orangejuice, stored under the same conditions as sample A.

The result was as follows: visually, no one could see any differencebetween the two samples. To most people in the panel the samples tasteddifferent but no one reported an unpleasant taste. This shows that thepolyunsaturated fatty acids in the drink according to the invention didnot turn perceptibly rancid over a period which was considerably longerthan the normal storage time for the water-based phase.

1. A method for manufacturing a liquid nutritional and refreshingpreparation comprising a water-based liquid phase and an emulsion whichhas a storage time being at least that of the liquid phase alone withoutbecoming rancid, the method comprising first, producing an emulsioncontaining 65–90 weight % liquid oil containing at least 15 weightpercent omega-3 fatty acids in a lipid phase and an emulsifying agent ina hydrophase, wherein aromatic oil, sweetening agent, pH-regulatingagent, water, preserving agents, vitamins, and antioxidants are combinedwith the emulsion; second vigorously stirring the emulsion into an addedwater-based liquid phase in such a manner that the emulsion isdistributed homogeneously in the water-based liquid phase and the ratiobetween the lipid phase and the hydrophase in the emulsion is unaltered.2. A method as specified in claim 1, wherein the emulsion is composed of80% of fish oil with 40% omega-3, fatty acids 0.5% egg yolk, 1% lemonoil, 4.8% sugar, 1% salt, 2% citric acid, 5% H₂O, 0.5% preserving agentsfrom the group consisting of sodium benzoate, potassium sorbate andmethyl parahydroxy benzoate, 0,6% ascorbic acid, 0.1% vitamin E, allbased on weight.
 3. A method as specified in claim 1, wherein the oilcomprises vegetable oil or marine oil, alone or in combination.
 4. Amethod as specified in claim 1, wherein the emulsion contains 66–88%weight % fish oil, and the emulsifying agent is egg yolk.
 5. A method asspecified in claim 1, wherein the ratio between emulsion and water phaseis from 1:10 to 1:100.
 6. The method as specified in claim 5, whereinthe ratio between emulsion and water phase is from 1:20 to 1:40.
 7. Amethod as specified in claim 1, wherein the water-based liquid phase isselected from the group consisting of sugary drinks, mineral water,fruit cider, fruit juice, milk, breast milk substitute, coffee or tea.8. A method as specified in claim 7, wherein the water-based liquidphase is breast milk substitute.
 9. A method as specified in claim 1,wherein the water-based liquid phase is orange juice.
 10. A method asspecified in claim 1, wherein the liquid nutritional and/or refreshingpreparation contains 4 weight % fish oil with 40% omega-3 fatty acids,0.25 weight % egg yolk, 0.05 weight % lemon oil or orange oil, 0.239weight % sugar, 0.05 weight % salt, 0.1 weight % citric acid, 0.25weight % water, 0.025 weight % preserving agents from the groupconsisting of sodium benzoate, potassium sorbate and methyl parahydroxybenzoate, 0.03 weight % vitamin C (ascorbic acid), 0.005 weight %vitamin E and 95 weight % orange juice containing 57 g ascorbic acid.11. A method as specified in claim 1, wherein the resulting liquidnutritional and/or refreshing preparation contains 13 grams of omega-3fatty acids per 1000 ml of drink.